Baffle type muffler with corrugated casing



Oct. 18, 1949. HARLEY 2,484,827

BAFFLE TYPE MUFFLER WITH CORRUGATED CASING Filed 001;. 1'7, 1946 2 Sheets-Sheet l INVENTOR: Bertrdn G. Hurley Oct. 18, 1949. B. s. HARLEY BAFFLE TYPE MUFFLER WITH CORRUGATED QASING 2 Sheets-Sheet 2 Filed Oct. 17, 1945 H Z P2 INVENTOR.

Bertron G. Harley Patented Oct. 18, 1949 UNITED STATES PATENT OFFICE BAFFLE TYPE MUFFLER WITH CORRUGATED CASING This invention relates to pulsation dampeners which may include, for example, mufflers or exhaust silencers for combustion engines and particularly automotive engines. It is among the objects of the invention to produce a dampener or muffier that is simple, compact and inexpensive to manufacture. Another object is to provide an eficient mufiler consisting of a minimum of parts, preferably not more than two.

This invention proposes to dampen or silence undesired pulsations in a gas stream by subdividing such stream into a plurality of component sub-streams and, during their passage through the muffler, make varying directional changes in each and setting up neutralizing effects on one another by making these directional changes tortuous. The latter bring about certain silencing effects as parts of one sub-stream impinge on parts of another sub-stream or as they intersect with each other.

One feature of this invention is embodied in a dampener or mufller that is made up of a pair of pan-like shells each of which is provided with undulated or corrugated faces. The corrugations are made up of valleys, grooves or channels forming ridges or peaks between them in such a manner that when the shells are placed together face to face, i. e., in opposed but symmetrical fashion to provide the muffling space between them, the valleys and ridges in one shell complement or co-act with the valleys and ridges of the other shell to constitute an efficient dampening or muffling baffle system which is realized and becomes effective as such incident to the mere assembly and securing together of two such shells.

A further feature of the invention resides in that when the shells are secured together in dampening or muffling relationship, the ridges and valleys of one shell lie at an angle less than 130 apart relative to those of the other shell and preferably nearer to 90 apart. These valleys and ridges of a shell thus lie at an angle of less than 180 to the longitudinal axis of that shell. In an X-ray view through the assembled mufrler. the ridges and valleys of one shell would appear to intersect the valleys and ridges of the other shell but since in reality the valleys and ridges of one shell lie in a different plane from those of the other shell, the valleys and ridges of the two shells do not actually intersect but grooves of one shell overlie the grooves of the other shell at an angle so the grooves and edges of the one shell traverse the grooves and ridges of the companion shell. This enables the gases to pass from one shell to the other in a multiplicity of tortuous directional changes. Hence, the term intersecting is to be thus understood in defining the angular disposition of the ridges of one shell relative to the ridges of the companion shell. The shells preferably are stamped out of metal and their corrugations formed during the stamping process. Therefore, the corrugations appear on each side of each shell, namely on the outer face thereof as well as on the interior face thereof. Of course, when corrugations are formed in this Way, what is a ridge on the outside face of a shell becomes a valley or groove" on the inner face or inside of the shell, while a valley or groove on the outside becomes a ridge on the inside, and so on. 1

According to another definition of one embodiment of this invention the muffler comprises a pair of companion pan-like shells assembled in symmetrical fashion with a general longitudinal flow-path therethrough. Each shell has a set of parallel diagonally extending baflles rising from the interior face of the shell presenting free bafiie edge portions. By assembling a pair of shells the baffle edge portions of the one shell are placed in proximity with the bafile edge portions of the companion shell although in traversing or intersecting relationship thereto. The assembling of the shells establishes a co-action of the respective sets of bafiles with each other whereby an effective dampening system is attained.

According to another feature, each shell also has a portion that is depressed on the outside of the shell but is raised on the inside of the shell and is disposed in such a manner that when the shells are placed together in a symmetrical fashion, the internally raised portions are aligned and abut so as to be complementary to each other in constituting a primary baffle at the inlet end of the dampener or muffler that is effective to split the entering gas stream in such a manner that one portion of the gas stream is guided to enter one set of diagonally disposed grooves or channels and the other portion is guided to enter the other set of differently inclined diagonal grooves or channels.

The invention possesses other objects and features of advantage, some of which with the foregoing will be set forth in the following description. In the following description and in the claims, parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the claims hereof will permit. In the accompanying drawings there has been illustrated the best embodiment of the invention known to me,

but such embodiment is to be regarded not as limiting but as typical only of many possible embodiments and structural arrangement.

The novel features considered characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings in which Fig. 1 is a view upon one diagonally grooved side of the dampener or muffler;

Fig. 2 is a part-sectional View taken on the line 2-2 in Fig. 1;

Fig. 3 is a view upon the opposite diagonally grooved side of the muifler;

Fig. 4 is an end view taken on line 4-4 in Fig. 1;

Fig. 5 is a cross-sectional view taken on line 5--5 in Fig. 1;

Fig. 6 shows two identical half shells apart and with their swaging edge portions open;

Fig. 7 is a perspective of the half shells in Fig. 6 illustrating the structural and manufacturing identity of the two shells;

Fig. 8 is an idealized diagram of component flow-paths of the gases passing through the muffier illustrating the neutralizing interferences among them;

Fig. 9 is an idealized diagram of one of the component streams illustrating hypothetical flowpaths resulting from a further subdivision into sub-component streams and also illustrating the potential interferences among them.

The muiiier comprises a pair of pan-like shells ill and l l which are identically shaped but in such a manner as to enable them to be assembled in symmetrical fashion and swaged together as will be further described below. Because of their structural identity the detailed description of one shell Ill will sumce.

Such a shell has a longitudinal pan-shaped body portion lil having an edge portion l3 in the form of a male swaging flange and an opposite edge portion i in the form of a female swaging flange. t one end of the body portion the edge portion interrupted by a longitudinal channelshaped portion 45 representing one longitudinal half of an inlet neck I of the muiiler. At the opp site end the body portion is provided with a at i M longitud n l chann l-Shaped portion l6 representing one longitudinal half of an outlet neck O of the muffler. The inlet and outlet neck portions shown to be in line with the longitudinal central axis of the muflier.

The body portion ii. is formed with internal ridges of different lengths although collectively designated by the character R which extend diagonally of the longitudinal axis of the body portion whereby there are created channels or grooves of corresponding lengths collectively designated by the character G, the angle of inclinaticn of the ridges relative to the longitudinal axis being shown to be about at 45. These ridges rising from the .ltorior face of the pan-shaped having free edge portions conn the mufiler in a manner scribed.

in this pattern of ridges and grooves the ridges R comprise a pair of long ridges ll and N a pair of slightly shorter ridges l8 and 18 and a pair of short ridges l9 and 19. The channels G comprise a long channel 28, a pair of slightly shorter channels 2! and 2 l and a pair of shortest channels 22 and 22 There is also provided a transverse ridge 23 facing the inlet neck portion I.

The end View of two shells l0 and l I constituting the mufiier in Fig. 6 shows them apart although in position about to be assembled and joined. In assembling the shell II is placed face to face with its companion shell I!) so that the respective edge portions M can be swaged over their associated edge portions [3 as indicated at [4- in Fig. 5. This assembly places free edge portions of one set of ridges R, that is the ridges in one shell, in traversing or intersecting relationship and in proximity if not actual contact with the free edge portions of the ridges of the companion shell. Such traversing relationship is indicated by the X-ray (dotted line) showing in Fig. 1 of the ridges at the far side of the muffler. This also places the free edge portions of the transverse ridges 23 of one shell in proximity and registry with the corresponding free edge portions of the ridges 23 of the companion shell so as to constitute a baffle B in the path of the infiowing stream of gases entering the inlet neck I of the muffler. This baffle B, herein briefly termed the inflow-splitting inlet baille, offers to the incoming stream a convex face 24 and has a correspondingly concave face 25 in the rear.

The interior or the muffler (see Figs. 1 and 3) may be defined as by an inlet space or zone a containing the primary baffle B for splitting the incoming stream into two portions-a zone b which is the baffling zone constituted by the two sets of intersecting ridges and grooves; and a zone 0 which is the outlet zone where the component streams emerging from the grooves combine and whence they pass from the muiller.

Diagrammatic idealized views in Figs. 8 and 9 illustrate how the silencing effect is created in this muliler by subjecting the entering main 3- stream of the gases to split-ups into component streams as well as to tortuous directional changes While causing these streams to intersect with one another. I According to Fig. 8 a stream 25 of gases indicated by a family of six cognate stream lines enters the muiller M schematically shown to be split in half by the inlet bailie B, namely a stream portion 26 indicated by three stream lines 26, 28 and 26 and another stream portion 21 indicated by three stream lines 21 21 and 21 This primary helixing or split-up guides one portion towards and into one set of inclined grooves G and another portion into the opposite set of grooves G.

Thus, according to one idealized concept, the stream lines 26 26 and 26 will intersect with the opposed stream lines 21 21 and 2'! as at points P1. An example of stream lines of the same portion, say, portion, intersecting with one another is represented by intersection points P2.

All stream lines emerging from the baflle zone 17 join in a stream 28 in the zone 0 to pass from the muilier through the outlet neck thereof.

An idealized concept illustrated in Fig. 9 shows a single isolated stream line 29 being initially deflected by baffle B, then divided into component streams such as represented by the undulating lines 29. These undulating lines result when a component stream is repeatedly directed from the diagonal direction in one groove into the diagonal direction of adjacent traversing grooves as the stream passes back and forth between the two companion shells of the muiller. Superimposed upon this pattern of undulating component streams there is shown a pattern of component streams which intersect with one another as at points P3, although the component streams are shown to join again by forming a stream 3%) passing through the outlet neck of the mufller.

While the embodiment herein shown has the inlet and the outlet neck disposed in line with the longitudinal central axis of the muffler, the underlying principles of function, and of structure can also be embodied in a mufiler having off-center inlet ancl/ or outlet connections.

An advantage of this muffler construction lies in the fact that before assembling the shells can be nested in stock to conserve shipping space, to be assembled in the manner above described at their point of destination.

I claim:

1. A pulsation dampening device for exhaust gases having a general flow-path substantially longitudinally therethrough comprising a pair of companion pan-like shells, the bottom portion of each of said shells being formed with impressions extending diagonally of the flow-path and constituting substantially a wave-like cross-sectional pattern resembling corrugations which inwardly present ridges constituting flow baffle portions which bafile portions outwardly present corresponding grooves having corresponding outer cooling surfaces, the bafile portions of the one shell lying adjacent to and extending transversely of similar bailie portions of the other shell to constitute a dampening device when the two shells are assembled with their inner sides facing each other.

2. A device according to claim 1, in which the shells are substantially identical, each shell having a female swedging flange along one side and a male swedging flange along the other side.

BERTRON G. HARLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

